Plz help me with shutdown + inverter....I'm almost there.

08-23-2004, 12:19 PM

OK I've been reading over this thread for the past week. I finally think I'm getting it, but I just need some final clarification.

Question 1: In Laidback's design he has a diode in line with the acc line. Should this diode be in between battery and inverter as well in front of the computer? If anything in this statement is untrue please let me know.

Question 2: One concept I'm having a hard time understanding deals with the inverter shutting off therefor not allowing power to go to the computer. In my feable mind this should mean once the power is cut the computer can not shut down properly. I'll be using Laidback's diagram. That said how does the computer properly shut down if it isn't supplied power? I'm assuming it has something to do with the relay or this UPS shutdown feature in windows, but I'm not sure. I honestly don't want to go through designing and wiring this up just to find out it won't work with my install.

Comment

The 2 diode allow the relay to be triggered by the 2 source without the 2 source conflicting with each other. In this case the sources of relay triggering is from the IGNITION and the PC 12V supply. When you switch on the IGNITION the relay will then close its contact therefore turning the inverter on...swithing the PC on and also "holding" the relay to on position...you have now 2 sources of voltage holding the relay in on position.

Once you turn the IGNITION off, the PC +12V supply can still hold the relay in the on position and therefore keeping the power into the inverter, keeping the PC on. Once a shutdown is initiated the PC then goes off after 30secs or so...the PC+12V then goes off killing the only supply to keep the relay in that on position. Because you have already turned the IGNITION off and the PC is no longer on the relay therefore cut the power to the inverter.

Hope that helps...I think Im breathless now

Why not ask Laidback for further info?

Comment

The 2 diode allow the relay to be triggered by the 2 source without the 2 source conflicting with each other. In this case the sources of relay triggering is from the IGNITION and the PC 12V supply. When you switch on the IGNITION the relay will then close its contact therefore turning the inverter on...swithing the PC on and also "holding" the relay to on position...you have now 2 sources of voltage holding the relay in on position.

Once you turn the IGNITION off, the PC +12V supply can still hold the relay in the on position and therefore keeping the power into the inverter, keeping the PC on. Once a shutdown is initiated the PC then goes off after 30secs or so...the PC+12V then goes off killing the only supply to keep the relay in that on position. Because you have already turned the IGNITION off and the PC is no longer on the relay therefore cut the power to the inverter.

Comment

I take that back. How do I get 12V from the psu. The lines running from the power supply have only shown me 5V on my multimeter. If I can get help on that one thing I can work this up over the w/e or maybe one evening after work.

Comment

Once you turn the IGNITION off, the PC +12V supply can still hold the relay in the on position and therefore keeping the power into the inverter, keeping the PC on. Once a shutdown is initiated the PC then goes off after 30secs or so...the PC+12V then goes off killing the only supply to keep the relay in that on position. Because you have already turned the IGNITION off and the PC is no longer on the relay therefore cut the power to the inverter.

Hope that helps...I think Im breathless now

Why not ask Laidback for further info?

Ok maybe two questions. How is the shutdown initiated? If I'm understanding this correctly the shut down of the pc would still be manual, right?

Comment

I take that back. How do I get 12V from the psu. The lines running from the power supply have only shown me 5V on my multimeter. If I can get help on that one thing I can work this up over the w/e or maybe one evening after work.

Comment

Ok so what tells the +5v to go to 0v? The fake UPS? Thats the meat of my question and the real cause of my confusion. Once I've taken the key out and the pc's power supply is the only thing keeping the relay open what happens then to tell the computer to cut the +5v going into com port pin 8. I'm just not understanding how the pc cuts the +5v before it actually shuts down and if it can do this what is forcing it to. Thanks alot for all the help guys.

Comment

Ok so what tells the +5v to go to 0v? The fake UPS? Thats the meat of my question and the real cause of my confusion. Once I've taken the key out and the pc's power supply is the only thing keeping the relay open what happens then to tell the computer to cut the +5v going into com port pin 8. I'm just not understanding how the pc cuts the +5v before it actually shuts down and if it can do this what is forcing it to. Thanks alot for all the help guys.

The car cuts the +5v when you turn the ign off, via a relay. Or you could just put +12v ACC straight to the com port pin 8.

Comment

So I need two relays? I think that's what was confusing me because I only see one in your diagram. I think I'll just go with one relay and send 12v to pin 8 from an ACC line. That seems to be the simplest way for me. That way I cut the ACC. It cuts the 12v to pin 8 initiating shutdown. Per Ricky's explanation the relay ACC current will be cut and the only thing keeping the relay open is the 12v from psu. Once pc has completely shutdown 12v from psu shuts off then inverter shuts off. Very nice. I guess my only issue is I hate to send 12V to pin 8 if I only need to send 5V. Last question is there a place in windows that you can tell the pc to hibernate on shutdown because I don't believe my bios has this option.

Comment

So I need two relays? I think that's what was confusing me because I only see one in your diagram. I think I'll just go with one relay and send 12v to pin 8 from an ACC line. That seems to be the simplest way for me. That way I cut the ACC. It cuts the 12v to pin 8 initiating shutdown. Per Ricky's explanation the relay ACC current will be cut and the only thing keeping the relay open is the 12v from psu. Once pc has completely shutdown 12v from psu shuts off then inverter shuts off. Very nice. I guess my only issue is I hate to send 12V to pin 8 if I only need to send 5V. Last question is there a place in windows that you can tell the pc to hibernate on shutdown because I don't believe my bios has this option.

The comport should be able to take up to 25v, so 12v should be no problem (Notice I say 'should' a lot! )

Comment

Well I could always throw a fuse(something I really understand) in line with the 12v going to the comport just for safety. Also I still don't really know how to set up a relay for that part of the design. I understand the inverter side and it's relay, but I end up right back at my earlier questions for the comport side and it's relay.